Nylander was selected 12th overall by the Mississauga Steelheads of the Ontario Hockey League at the 2015 Canadian Hockey League Import Draft. On 5 September 2015, Nylander committed to Steelheads with his father joining as assistant coach. His reasons for joining include being close to his brother William and to have the chance to play the Canadian style of hockey. In his only season with the Steelheads, Nylander led all rookies in scoring, and was awarded both the Emms Family Award as OHL Rookie of the Year and CHL Rookie of the Year. Leading up to the NHL draft, Nylander was ranked the No. 3 North American skater. He was described as a dynamic offensive player with a great shot and playmaking ability.
Professional
Nylander was selected 8th overall by the Buffalo Sabres in the 2016 NHL Draft. On 15 July 2016, the Sabres signed Nylander to a three-year entry-level contract. Nylander was called up to the NHLfor the first time on 3 April 2017, to play in a game against the Toronto Maple Leafs. Nylander played 14:28 minutes during the 4–2 loss. After playing four games in the NHL he was reassigned back to their AHL affiliate, the Rochester Americans. The Sabres assigned Nylander to their AHL affiliate before finalizing their roster for the 2017–18 season. Nylander suffered a lower-body injury in mid-September during the Buffalo Sabres' first prospect game, causing him to miss the rest of the training camp and the beginning of the 2017–18 AHL season. He returned to the lineup on 17 November 2017, for a game against the Hartford Wolf Pack. Despite a slow start, Nylander was called up to the NHL on 3 April 2018. He recorded his first career NHL goal on 6 April 2018 in a game against the Tampa Bay Lightning. After the Sabres failed to qualify for the 2018 Stanley Cup playoffs, Nylander was reassigned to the AHL. On 9 July 2019, Nylander was traded by the Sabres to the Chicago Blackhawks in exchange for fellow first-rounder Henri Jokiharju and opted to wear sweater #92 with the club, the same number his father wore.
Alexander was born in Calgary while his father, Michael, played for the Calgary Flames. He spent the majority of his youth in the United States where his father played for a multitude of NHL teams, and spending the summers in Sweden. His older brother, William plays for the Toronto Maple Leafs. He was also drafted 8th overall, 2 years earlier.
